Voltage-gated potassium currents in rat vas deferens smooth muscle cells

Voltage-gated components of the outward current in single smooth muscle cells isolated from the epididymal part of the rat vas deferens were studied using amphotericin B perforated patch-clamp techniques. The complex kinetics of the net outward current elicited by positive voltage steps from -80 mV to +40 mV suggested the presence of several components. Bath application of 200 nM charybdotoxin, a potent blocker of large-conductance, Ca(2+)-dependent K(+) channels (BK(Ca)), reduced the current amplitude significantly. When BK(Ca) channels were suppressed, fast-inactivating (I(K,f)) and delayed rectifying (I(K,dr)) components of the outward current were identified. I(K,f) was characterized by fast kinetics of current decay, negative steady-state activation and inactivation dependencies and sensitivity to 4-aminopyridine with an apparent K(d) of 0.32 mM, properties similar to those of the A-type K(+) current. In contrast, I(K,dr) activated and inactivated at more positive potentials. The time constant of activation of I(K,dr) was voltage dependent with an e-fold decrease per 21 mV depolarization. I(K,dr) was inhibited by clofilium, a blocker of voltage-gated K(+) channels, with an IC(50) of 12 micro M and was not blocked by 5 mM 4-aminopyridine. The possible significance of the voltage-gated currents is discussed.     

Role of extracellular Ca2+ in gating of CaV1.2 channels

We examined changes in ionic and gating currents in Ca_V1.2 channels when extracellular Ca²⁺ was reduced from 10 m m to 0.1 μ m . Saturating gating currents decreased by two-thirds ( K _D≈ 40 μ m ) and ionic currents increased 5-fold ( K _D≈ 0.5 μ m ) due to increasing Na⁺ conductance. A biphasic time dependence for the activation of ionic currents was observed at low [Ca²⁺], which appeared to reflect the rapid activation of channels that were not blocked by Ca²⁺ and a slower reversal of Ca²⁺ blockade of the remaining channels. Removal of Ca²⁺ following inactivation of Ca²⁺ currents showed that Na⁺ currents were not affected by Ca²⁺-dependent inactivation. Ca²⁺-dependent inactivation also induced a negative shift of the reversal potential for ionic currents suggesting that inactivation alters channel selectivity. Our findings suggest that activation of Ca²⁺ conductance and Ca²⁺-dependent inactivation depend on extracellular Ca²⁺ and are linked to changes in selectivity.     

Agentive and communitarian play in early childhood

Play has long been recognised as a vehicle by which significant developmental advances occur during early childhood. Children use play to explore their relationships, their psychosocial skills, and their environment, and through their experiences, they begin to adopt specific capacities and values that have an impact on future socio-emotional and academic outcomes. To understand more fully the factors that contribute to well-being in early childhood, we explored footage of a full ‘day in the life’ of a 5-year-old boy in transition to kindergarten, and we conducted interviews with him, his parents, and teacher. We identified agentive and communitarian strivings to be significant sources of his thriving and primary elements of many episodes of play during his filmed day. Previous research indicates that the development of strong agentive and communitarian skills and values is related to positive psychosocial outcomes. The current case study explores our participant's agentive and communitarian behaviours as exemplified through episodes of play, and the ways in which these skills and values are encouraged and supported by his caregivers. Implications regarding the role of parents and educators in the facilitation of agentive and communitarian skills are discussed.     

Effectiveness of inhaled hypertonic saline application for sputum induction to improve Mycobacterium tuberculosis identification in patients with pulmonary tuberculosis

Wiener Medizinische Wochenschrift - This study assessed the effectiveness and diagnostic significance of hypertonic saline sputum induction for improving Mycobacterium tuberculosis (MTB) detection....     

A nickel–titanium memory-shape device for gastrojejunostomy: comparison of the compression anastomosis clip and a hand-sewn anastomosis

Background

The aim of this study was to evaluate the efficacy of a compression anastomosis clip (CAC) for gastrojejunostomy and comparison of a novel technique with a hand-sewn anastomosis.

Methods

Sixty-six patients underwent gastrojejunostomy with the CAC or hand-sewn anastomosis. The time of bowel function recovery, the duration of nasogastric drainage, the time of initiation of oral feeding, the duration of postoperative hospital stay, the time needed to expel the clip, and the observation of any complications were recorded.

Results

Neither group had anastomotic complications such as leakage or obstruction. Anastomosis time was shorter in the CAC group than in the control group (P < 0.01). The mean time of clip expulsion was 15.1 ± 6.04 d. There was no statistical difference in postoperative results between the two groups. There was a moderate positive correlation between the day of first bowel movement and the day of clip expulsion (r = 0.536) and a strong correlation between the duration of nasogastric drainage and the day of clip expulsion (r = 0.881).

Conclusions

The method of using a CAC appeared to be safe, easy, inexpensive, and less time consuming. It should be taken into consideration that intra-abdominal complications may cause delayed CAC expulsion.     

A graphene-based hybrid material with quantum bits prepared by the double Langmuir–Schaefer method

The scalability and stability of molecular qubits deposited on surfaces is a crucial step for incorporating them into upcoming electronic devices. Herein, we report on the preparation and characterisation of a molecular quantum bit, copper(ii)dibenzoylmethane [Cu(dbm)₂], deposited by a modified Langmuir–Schaefer (LS) technique onto a graphene-based substrate. A double LS deposition was used for the preparation of a few-layer-graphene (FLG) on a Si/SiO₂ substrate with subsequent deposition of the molecules. Magnetic properties were probed by high-frequency electron spin resonance (HF-ESR) spectroscopy and found maintained after deposition. Additional spectroscopic and imaging techniques, such as Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscopy (SEM) were performed to characterise the deposited sample. Our approach demonstrated the possibility to utilise a controlled wet-chemistry protocol to prepare an array of potential quantum bits on a disordered graphene-based substrate. The deployed spectroscopic techniques showed unambiguously the robustness of our studied system with a potential to fabricate large-scale, intact, and stable quantum bits.

Graphene-based hybrid material with array of copper(ii)-based quantum bits was prepared by a wet-chemistry protocol and characterised by HF-ESR, XPS, Raman, and AFM.     

Fused Thiopyrano[2,3-d]thiazole Derivatives as Potential Anticancer Agents

rel-(5aR,11bR)-3,5a,6,11b-tetrahydro-2H,5H-chromeno[4′,3′:4,5]thiopyrano[2,3-d][1,3]thiazol-2-ones formed by the stereoselective Knoevenagel-hetero-Diels-Alder reaction were functionalized at the nitrogen in position 3 via reactions of alkylation, cyanoethylation, and acylation. The synthesized compounds were evaluated for their anticancer activity in NCI60 cell lines. Among the tested compounds, 3f was found to be the most active candidate with the greatest influence on leukemia, non-small cell lung cancer, colon cancer, CNS cancer, melanoma, prostate cancer, and breast cancer subpanel cell lines with GI₅₀ values over a range of 0.37–0.67 μM.     

Fermented wheat germ extract induces apoptosis and downregulation of major histocompatibility complex class I proteins in tumor T and B cell lines

The fermented wheat germ extract (code name: MSC, trade name: Avemar), with standardized benzoquinone content has been shown to inhibit tumor propagation and metastases formation in vivo. The aim of this study was to understand the molecular and cellular mechanisms of the anti-tumor effect of MSC. Therefore, we have designed in vitro model experiments using T and B tumor lymphocytic cell lines. Tyrosine phosphorylation of intracellular proteins and elevation of the intracellular Ca2+ concentration were examined using immunoblotting with anti-phosphotyrosine antibody and cytofluorimetry by means of Ca2+ sensitive fluorescence dyes, Fluo-3AM and FuraRed-AM, respectively. Apoptosis was measured with cytofluorimetry by staining the DNA with propidium iodide and detecting the cell population. The level of the cell surface MHC class I molecules was analysed with indirect immunofluorescence on cytofluorimeter using a monoclonal antibody to the non-polymorphic region of the human MHC class I. MSC stimulated tyrosine phosphorylation of intracellular proteins and the influx of extracellular Ca2+ resulted in elevation of intracellular Ca2+ concentration. Prominent apoptosis of 20-40% was detected upon 24 h of MSC treatment of the cell lines. As a result of the MSC treatment, the amount of the cell surface MHC class I proteins was downregulated by 70-85% compared to the non-stimulated control. MSC did not induce a similar degree of apoptosis in healthy peripheral blood mononuclear cells. Inhibition of the cellular tyrosine phosphatase activity or Ca2+ influx resulted in the opposite effect increasing or diminishing the Avemar induced apoptosis as well as the MHC class I downregulation, respectively. A benzoquinone component (2,6-dimethoxi-p-benzoquinone) in MSC induced similar apoptosis and downregulation of the MHC class I molecules in the tumor T and B cell lines to that of MSC. These results suggest that MSC acts on lymphoid tumor cells by reducing MHC class I expression and selectively promoting apoptosis of tumor cells on a tyrosine phosphorylation and Ca2+ influx dependent way. One of the components in MSC, 2,6-dimethoxi-p-benzoquinone was shown to be an important factor in MSC mediated cell response.